The present invention relates to an examination chair serving in particular to enable a practitioner to treat positional vertigo. The medical examination chair thus allows a seated person to be moved in a multidirectional mode and over large amplitudes, which is useful in dealing with such vertigo.
The inner ear of a human being enables the brain to identify the movements to which the person is subjected by means of three semicircular canals that are oriented in three substantially perpendicular planes. In addition, the vestibule receiver organ of the inner ear includes a zone that informs the brain on acceleration/deceleration phenomena, said zone being constituted in part by a gelatinous mass weighted by small crystals known as “otoliths” to the person skilled in the art. Positional vertigo can then be caused by the following phenomena that lead to erroneous perception of movements:                cupololithiasis caused by otoliths becoming detached and then migrating to the cupola cochlea which is a very sensitive portion of a semicircular canal; or        canalolithiasis caused by otoliths that become detached and that move about in a semicircular canal.        
While making a diagnosis, the practitioner moves the trunk and the head of the patient slowly through 180° in three planes: from front to back, laterally from one side to the other, and then in rotation about the axis of the body.
If positional vertigo is diagnosed, the practitioner moves the trunk and the head of the patient in a given plane rapidly followed by sudden deceleration. Thus, the otoliths that give rise to vertigo are expelled from the sensitive zone and the vertigo is generally cured in one to three sessions.
An examination chair is known that presents mobility about a vertical axis enabling a sitting patient to be turned. It is also possible to tilt the back of the chair so as to put the patient into a prone position, and it is also possible to lift the chair relative to its stand, usually by means of an electrically-controlled rack system, or possibly by a foot-controlled hydraulic system. This kind of chair mobility is largely sufficient for most examinations. However, the manipulations associated with diagnosing and treating positional vertigo cannot all be performed, since movement is possible in a single plane only and the manipulations are also wearisome both for the patient and for the practitioner.
Document FR 1 113 809 discloses apparatus for rehabilitation and checking reflexes, which apparatus includes an oscillating support, preferably having a plurality of degrees of freedom in movement, on which the patient is placed in such a manner as to be capable of damping or amplifying the oscillations of the support by moving the patient's own center of gravity.
That document is remote from the technical field of treating vertigo. The object of the device described is to stimulate the reflexes of a handicapped person, and not to move otoliths in the inner ear that lead to positional vertigo. In addition, it does not make it possible in any way to impart rapid movement followed by sudden deceleration.
The manipulations associated with diagnosing and treating vertigo therefore cannot be implemented in satisfactory manner with a device of known type.
Such manipulations are thus generally performed on an examination couch and they require a large amount of physical strength and know-how on the part of the practitioner, and also excellent co-operation on the part of patients. Unfortunately, this cannot be achieved with patients suffering from arthrosis, obesity, handicaps, or high levels of anxiety, which patients are consequently particularly difficult to treat, and that can lead to therapy failing.
In addition, the need to have available in a medical office both an examination couch and an examination chair considerably increases the amount of space that is needed and also the costs inherent in fitting out an office.